Fire-retardant cellulosic compositions

ABSTRACT

A FLAME-RETARDANT COMPOSITION COMPRISED OF A CELLULOSIC COMPOSITION AND A BIS-B,B-(DIALKYLPHOSPHONO) PROPIONIC ACID DERIVATIVE INTEGRALLY ATTACHED TO THE CELLULOSIC POLYMER CHAIN OF THE CELLULOSIC COMPOSITION.

.geg g a i? EsFS SiQia-WYQ 3,560,479 FIRE-RETARDANT CELLULOSIC COMPOSITIONS ChandraPnnde, Farmingdale, N.Y., assignor to s. or. 250-212 was thereby rendered- Borg-Warnei-Corporation, Chicago, Ill. No Drawing. Filed Oct. 21, 1969, Ser. No. 868,215 Int. Cl. C08b 23/00, 27/66, 27/68 6 Claims .Ans'rnAcr on "ma DISCLOSURE flame-retardant composition comprised of a celj lulosic composition and a 'bis-fl,fi-(dia1kylphosphono.)

propionic acid derivative integrally attached to the cellulfosic, polymer chain of thevcellulosic composition.

BACKGROUND OF INVENTION Prior to this invention, there werenumerous methods of treating cellulosic compositions to impart flameretardant characteristics thereto. Perhaps the most efficient and well-known manner of providing flameretardant properties tocellulosic was, to add chlorinated hydrocarbons as well as antimony oxide as a rinse on the cellulosic fabric or sheet to deposit the flame-retardant compound on the surface thereof. The fabric or sheet less flammable than it was prior totreatment.

In recent years, .phosphorus .compounds have been utilized to enhance the fire-retardant characteristics of cellulosic materialsand some of the phosphorus com pounds have been chemically reacted with cellulosic composition to provide a degree of flame-retardant characteristics to thecellulos'ic composition. One such treatment is set forth in United States Pat. 3,374,292 issued to Zahir. This patent-sets forth a treatment of cellulosic materials with sub s tituted phosphono amides as the reactant.

The aforementioned patent discloses a chemical com- 'bining of a flame-retardant compound with a cellulosic composition which-has been found to be superior to the blending of flame retardant components with cellulosic compositions. The useof the phosphorus-compound set forth in Pat. 3,374,292 is, however, somewhat limited in its effect onthefflaine-retardant characteristics of a cellulosic composition because it utilizes only one phos- .phono groupin'the phosphorus containing compound,

SUMMARY- OF INVENTION The present invention is direct, tollan'ie retardant cellulosic compositions provided by treating the cellulosic composition with; a disubstituted phosphono compound which is generally'referred to as a bis-p,B-(dialkylphosphono)propionic acid derivative: The propionic acid derivative is integrally-combined with the polymeric cellulosic chain and becomes'anin'tegral part of the cellulose molecule. Thus, the treating compound is not washed out of a fabric or frame; given cellulosic composition after treatment, even-though there may be repeated washings. 1

The compounds of this invention are generally described 3,560,419 fatented Feb. 2, 197 1 as bis-,8,/S-(dialkylphosphono)propionic acid compound which are generically described by the formula: v

3 ,tnonii CH-CHr-COX Rom wherein-R is an allryl group containing from 1 to Scar-hon atoms and X is selected from the group consisting of OR wherein R is" C1-C alkyl, NH, and NH-CI-LOH. The compounds-may bepreparedby reacting a-chloronerylonitrile, trialkyl phosphite and alcohol in accordance with the equation set forth herein below;

c1 r crn=c +.2(Ro),r non v v CN a 0 I (Mai I .on cmou 801+ BIO so u eri l-EQUATION I The cyano compounds prepared as set forth inEquat'ion I above may be: converted to the amido compound by either Equation lI- or Equation III as set forth herein 3 EQUATION III The amido compound set forth in Equation H may also be prepared in accordance with Equations IV and V set forth herein below:

CHI=C CONH:

+ 2010):? ROH (Email-i EQUATION 1v ll (ROMP CHEC-COOEt ztnonr zaoa ow s 43.0 g'. of bis-fifi-(diethylphosphono)propionitrile, 90.9 g. base ion exchange resin (Amberlite-400) and 250 ml. of water was refluxed under stirring for six hours. The ion exchange resin was filtered and the water was evaporated ca-cmcouu, RG1 Rio from the filtrate. A viscous oil (27.0 g.) formed. IR of NILIOII EQUATION V As set forth above, Equation IV shows the compounds as prepared from ethyl u-chloroacrylate Equation V from a-chloroacrylamide. and Equation VI from ethyl propiolate.

The amido compounds may be converted into their N- hydroxymethyl analogue according to Equation VI.

P CHCHzCONHCHzOH R 2 EQUATION VI The compounds that are used to chemically combine with cellulosic materials in accordancewith this invention may be prepared with a minimum of efiort. The examples set forth hereinbelow illustrate the preparation of the compounds and all parts in the following examples are by weight unless otherwise indicated.

' EXAMPLE I Preparation of N-hydroxymethyl-bE-Bfi- (diethylphosphono)propionamide Triethyl'phosphite (332 g.) was added to an ethanolic solution of a-chloroacrylonitrile (88.2 g. in 250 ml. ethanol). An exothermic reaction occurred. Upon complete addition of the a-chloroacrylonitrile,' the reaction mixture was refluxed for six hours. On fractionation it yielded bisfl,fl-(diethylphosphono)propionitrile.

fl p i Marrow) oucmom (265m 3. am, of yield) IR and NMR spectra confirmed the structure. The 8.1. of this compound was found to be 155 C./0.3 mm.

The above phosphono propionitrile was converted into the'correspo'nding bis 5,,8-(diethylphosphono)propionamide by using the following reaction:

this oil confirmed the formation of bis-p,fl-(diethylphosphono)propionamid'e.

The above propionamide (25.0 g.) was added to formalin (37% 15.0 g.) at 50-60 C., the pH of the mixture was maintained at 8.0-by adding aqueous sodium hydroxide solution drop by drop. After stirring for 1% hours, the mixture was cooled'to room temperature. On evaporation of the volatile fraction under reduced pressure, N,- hydroxymethyl bis-p.18-(diethylphosphono)propionamide was obtained.

EXAMPLE 11' Preparation of N-hydroxymethyl his-d,B-(diethylphosphono)propionamide from ethyl a-chloroacrylate Triethyl phosphite (220 g.) was added to an ethanolic solution of ethyl oc-chloroacrylate g. in 250 ml. ethanol). An exothermic reaction occurred. Upon complete addition of triethyl phosphite, the reaction mixture was refluxed for six hours. on, fractionation it yielded g. of ethyl bis-fi,,8-(diethylphosphono)propionate h) [uremia]: CIIClIzCOOEt, B.P. 160/0.4 mm.

' EXAMPLE III Preparation ofN-hydroxym e thyl bis-fi,fl-(diethylphospho- -no)propionamide from aw-chloroacrylamide (Equations IV and VI) Triethylphosphite (83.0'g'.) was added to a solution of et-chloroacrylamide (26.0'g.) in ethanol ml.). The reaction mixture wasrefluxedffor six hours. Excess ethanol was evaporated from the solution leaving bis-B,fi-(diethylphosphono)propionamide as a viscous colorless liquid (78 g.). IR spectra confirmed the structure.

This amide was converted to its N-hydroxymethyl derivative as described in Example I.

EXAMPLE IV Preparation of fl-(diethylphosphono)-,8-(dimethylphosphono)propionamide and its N-hydroxymethyl derivative I ll (mow ClI-CHr-CONHrarid (Meohill? 1 Formula I o (Etopi c'n-cnrcomromon (Meohfi v Formula II The I and II compounds above were synthesized according to the following equations:

37 ml. of methanolic solution of sodium methoxide (3 ml.) was slowly added to a mixture of fl-diethylphosphono aerylonitril'e (140 g. made from a known and. published reaction set. forth in 'Iiiebigs Annalen der Chemie, vol. 657, page 19, 1962) and dimethylphosphite (83 g.). An exothermic reaction occurred. After complete addition of the sodium methoxide, the reaction 5 mixture was heated'at 90 C. for one hour. Excess methanol and unreacted dimethyl phosphite were stripped off leaving a yellow-colored liquid. IR and NMR showed that the compound of the structure below resulted:

. (EtOhi CH-CHzCN (Meohfi A portion of the above (ca. 100 g.) was converted into its amide using water and an ion exchange resin according to the procedure described'in Example I for the conversion of the propionitrile derivative into a propionamide com pound.

The propionamide compound (Emi on omo ONH: (MeO)zP was converted into .the N-hydroxymethyl compound using 50 g. of the above propionamide and g. of formalin at pH 8 as describedin Example I.

' The compounds prepared in accordance with the examples set forth hereinabove are soluble in water and are capable of fire-retardant characteristics when chemically combined with, cellulosic materials such as cotton, paper and synthetic fabrics from cellulose as illustrated in Examples V and VI.

, EXAMPLE v Cotton fabric was padded with an aqueous solution containing the following ingredients:

, N-hydroxymethyl diethyl phosphonopropionamide 12.0 Aerotex CP Resin (cross-linking agent) 2.5 Cyanlube 0.25 Ammonium chloride (catalyst) 0.25

Urea 0.25

Water-(solvent) 9.0 A melamine-formaldehyde resin marketed by American Cyan'amid.

An American 'Cyanamid product which is a. mixture of lubricants such as fatty acid salt-s (used to provide "soft:

hand of fabric).

The impregnated fabric was dried and-was then heated at 165 C. for five minutes. The treated fabric was nonthis treated fabric was found to be self-extinguishing and no afterglow was observed even after repeated washings.

EXAMPLE VI Cotton fabric was padded with an aqueous solution containing the following ingredients:

N-hydroxymethyl derivative of Example IV 12.5 Aerotex Resin (cross-linking agent) 2.5 5 Cyanalube 0.25 Ammonium chloride (catalyst) 0.25 Urea 0.25 Water (solvent) 9.0

C A melamine-formaldehyde resin marketed by American xiiy inerlcan*Cyanamid product which is a mixture of lubricants such as fatty acid salts (used to provide "soft: hand" of fabric).

After drying and heating at 165 C. for five minutes, the fabric becamev non-burning or self-extinguishing.

It will be understood that while the invention has been described in connection with certain specific compounds that are used with certain specific cellulosic coinpositions, this is by way of illustration and not by way of limitation and that the scope of the invention is defined solely by the appended claims which should be construed as broadly as is consistent with the prior art.

What is claimed is:

1. The flame-retardant composition comprised of a cellulosic composition chemically combined with a bisburning to a vertical flame test. A washed sample of 7 5,5-(dialkylphosphono)propionic acid derivative of the generic formula: V

(ROh I 011-01114: 0X (noh l 0 wherein R is a C -C alkyl group and X is selected from the group OR wherein R is a C -C alkyl group consisting of NH, and NHCH OH wherein the bis-fifi-(di' alkylphosphono)propionic acid derivative is integrally attached to the cellulosic composition.

2. The flame-retardant composition of claim 1 wherein 15 the cellulosic composition is a fibrous cellulosic material. 3. The flame-retardant composition of claim 1 wherein the flame-retardant component in the cellulosic composition is N-hydroxymethyl-bis-fi,fl-(diethylphosphono) 6 6. The flame-retardant composition of claim 1. wherein the cellulosic composition is a cellulosic fabric.

References Cited UNITED STATES PATENTS 2,754,320 7/1956 Johnston 260-941 2,802,855 8/1957 Whetstone et al 260-941 3,093,672 6/1963 Miller 260-932 3,163,669 12/1964 Stilz et a1 260-941 3,205,034 9/1965 Chance 8-1162 3,284,540 11/1966 vDAlelio 260-869 3,351,617 11/1967 Iaeger et a1. 260-785 3,374,292 3/1968 Zahir 260-943 FOREIGN PATENTS 310,406 12/1955 Switzerland 260-941 DONALD E. CZAJ A, Primary Examiner R. W. GRIFFIN, Assistant Examiner UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,560,419 Da d February 2, 1911 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 10, before "OR' should read lines 10 and 11, cancel "consisting o consisting of Signed and sealed this 7th day of November 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Pat 

